It is known that the interior space of vehicles such as buses and recreational vehicles, or RV's as they are known in the art, is limited by the exterior dimensions of the vehicle and in particular the width of the vehicle. In many cases the width of the vehicle is limited by a maximum allowable width for vehicles traveling on conventional roadways. As an example, in some jurisdictions, the width of recreational vehicles is limited to approximately 8½ feet. However, when the vehicle has been parked, it is desirable to enlarge the useable interior space of the recreational vehicle beyond the maximum vehicle width allowable during use of the vehicle on the roadways.
One method to enlarge the useable space of the RVs is to provide an extendable compartment that has an exterior wall which is co-planar with the side wall of the RV for transportation. Such extendable compartments, known as slide-outs, may be extended relative to the RV when the vehicle has been parked. Slide-outs are typically slidably supported within an opening in a side wall of the RV and include one or more hydraulic cylinder, jack screw or rack and pinion mechanisms located below or along the sides of the slide-out for moving the slide-out between its extended and retracted positions. Examples of such slide-outs may be found in U.S. Pat. Nos. 6,796,590 to Schneider, 6,170,903 to Crean, 6,428,073 to Blodgett, Jr., 6,536,821 to Gardner, 5,860,686 to Tiedge, 6,325,437 to Hiebert, and 6,729,670 to Buls et al for example.
As owners have required larger living spaces in their RVs designers have responded by designing and building longer slide-out compartments. Such slide-out compartments may be 21 feet or more in length and have weights of 3000 pounds or more. A difficulty with building slide-outs of this length is the deflection of the middle portion of the slide-out when in the extended position. It will be appreciated that it is necessary to seal the opening of the RV around the slide-out both when the slide-out is extended as well as when the slide-out is retracted for transportation. Accordingly excessive deflection of the middle portion of the slide-out may cause the middle portion of the slide-out to rub against and damage the seal or may create too large of a gap between the wall of the RV and the slide-out to effectively seal due to the need to provide clearance for the deflection between these two components. Although support for the middle portion of the slide-out may help to reduce the amount of deflection, such intermediate support of the slide-out frequently interferes with the slide-out drive systems previously employed.
An additional difficulty with locating a drive mechanism for the slide-out below the slide-out compartment is the potential for water and debris to foul or otherwise damage the slide-out drive. However, previous slide-out drives have dictated this location due to the transverse length requirements of such system. In many RVs, there is limited or no space below the floor of the RV to contain such a drive mechanism.
An additional challenge in moving slide-outs in and out of RVs is that as the slide-outs get larger, and to accommodate the desire to extend slide-outs outwardly the maximum distance which may be obtained when constrained by the width of the RV, the drive mechanisms cantilever further and further outwardly from the slide-out support structure within the RV and those become increasingly unstable. In particular, the more pivotably inter-connected linkage members in a drive linkage and the greater the distance the linkage has to extend so as to extend the slide-out, the greater the tendency for the drive linkage to be “wobbly”, that is sufficiently unstable so that the slide-out may translate fore and aft relative to the RV (using the example of a slide-out in the side wall of an RV) during extension and during use of the slide-out while in its extended position.
As a general proposition, in applicant's view the greater the number of linkage members and pivoting connections in a drive linkage, the greater the tendency for the slide-out to wobble or shake when in its fully extended position so as to potentially adversely affect for example the seals around the slide-out. Thus it is one object among other objects of the present invention to provide a simplified drive mechanism and linkage to a single rotary drive and single linkage arm, whether unitary or telescopic, at each end wall and in mid-walls as necessary.
The method and apparatus of the present invention will thus minimally obstruct the end wall and will also enable a minimally obstructive support and drive apparatus to be located at a middle portion of the slide-out for greater support and load capacity.